1 files changed, 251 insertions, 280 deletions

diff --git a/net/netlink/genetlink.c b/net/netlink/genetlink.c
index 0c741cec4d0d..713671ae45af 100644
--- a/net/netlink/genetlink.c
+++ b/net/netlink/genetlink.c
@@ -65,12 +65,27 @@ static struct list_head family_ht[GENL_FAM_TAB_SIZE];
  * To avoid an allocation at boot of just one unsigned long,
  * declare it global instead.
  * Bit 0 is marked as already used since group 0 is invalid.
+ * Bit 1 is marked as already used since the drop-monitor code
+ * abuses the API and thinks it can statically use group 1.
+ * That group will typically conflict with other groups that
+ * any proper users use.
+ * Bit 16 is marked as used since it's used for generic netlink
+ * and the code no longer marks pre-reserved IDs as used.
+ * Bit 17 is marked as already used since the VFS quota code
+ * also abused this API and relied on family == group ID, we
+ * cater to that by giving it a static family and group ID.
+ * Bit 18 is marked as already used since the PMCRAID driver
+ * did the same thing as the VFS quota code (maybe copied?)
  */
-static unsigned long mc_group_start = 0x1;
+static unsigned long mc_group_start = 0x3 | BIT(GENL_ID_CTRL) |
+				      BIT(GENL_ID_VFS_DQUOT) |
+				      BIT(GENL_ID_PMCRAID);
 static unsigned long *mc_groups = &mc_group_start;
 static unsigned long mc_groups_longs = 1;
 
-static int genl_ctrl_event(int event, void *data);
+static int genl_ctrl_event(int event, struct genl_family *family,
+			   const struct genl_multicast_group *grp,
+			   int grp_id);
 
 static inline unsigned int genl_family_hash(unsigned int id)
 {
@@ -106,13 +121,13 @@ static struct genl_family *genl_family_find_byname(char *name)
 	return NULL;
 }
 
-static struct genl_ops *genl_get_cmd(u8 cmd, struct genl_family *family)
+static const struct genl_ops *genl_get_cmd(u8 cmd, struct genl_family *family)
 {
-	struct genl_ops *ops;
+	int i;
 
-	list_for_each_entry(ops, &family->ops_list, ops_list)
-		if (ops->cmd == cmd)
-			return ops;
+	for (i = 0; i < family->n_ops; i++)
+		if (family->ops[i].cmd == cmd)
+			return &family->ops[i];
 
 	return NULL;
 }
@@ -126,7 +141,9 @@ static u16 genl_generate_id(void)
 	int i;
 
 	for (i = 0; i <= GENL_MAX_ID - GENL_MIN_ID; i++) {
-		if (!genl_family_find_byid(id_gen_idx))
+		if (id_gen_idx != GENL_ID_VFS_DQUOT &&
+		    id_gen_idx != GENL_ID_PMCRAID &&
+		    !genl_family_find_byid(id_gen_idx))
 			return id_gen_idx;
 		if (++id_gen_idx > GENL_MAX_ID)
 			id_gen_idx = GENL_MIN_ID;
@@ -135,62 +152,113 @@ static u16 genl_generate_id(void)
 	return 0;
 }
 
-static struct genl_multicast_group notify_grp;
-
-/**
- * genl_register_mc_group - register a multicast group
- *
- * Registers the specified multicast group and notifies userspace
- * about the new group.
- *
- * Returns 0 on success or a negative error code.
- *
- * @family: The generic netlink family the group shall be registered for.
- * @grp: The group to register, must have a name.
- */
-int genl_register_mc_group(struct genl_family *family,
-			   struct genl_multicast_group *grp)
+static int genl_allocate_reserve_groups(int n_groups, int *first_id)
 {
-	int id;
 	unsigned long *new_groups;
-	int err = 0;
+	int start = 0;
+	int i;
+	int id;
+	bool fits;
+
+	do {
+		if (start == 0)
+			id = find_first_zero_bit(mc_groups,
+						 mc_groups_longs *
+						 BITS_PER_LONG);
+		else
+			id = find_next_zero_bit(mc_groups,
+						mc_groups_longs * BITS_PER_LONG,
+						start);
+
+		fits = true;
+		for (i = id;
+		     i < min_t(int, id + n_groups,
+			       mc_groups_longs * BITS_PER_LONG);
+		     i++) {
+			if (test_bit(i, mc_groups)) {
+				start = i;
+				fits = false;
+				break;
+			}
+		}
 
-	BUG_ON(grp->name[0] == '\0');
-	BUG_ON(memchr(grp->name, '\0', GENL_NAMSIZ) == NULL);
+		if (id >= mc_groups_longs * BITS_PER_LONG) {
+			unsigned long new_longs = mc_groups_longs +
+						  BITS_TO_LONGS(n_groups);
+			size_t nlen = new_longs * sizeof(unsigned long);
+
+			if (mc_groups == &mc_group_start) {
+				new_groups = kzalloc(nlen, GFP_KERNEL);
+				if (!new_groups)
+					return -ENOMEM;
+				mc_groups = new_groups;
+				*mc_groups = mc_group_start;
+			} else {
+				new_groups = krealloc(mc_groups, nlen,
+						      GFP_KERNEL);
+				if (!new_groups)
+					return -ENOMEM;
+				mc_groups = new_groups;
+				for (i = 0; i < BITS_TO_LONGS(n_groups); i++)
+					mc_groups[mc_groups_longs + i] = 0;
+			}
+			mc_groups_longs = new_longs;
+		}
+	} while (!fits);
 
-	genl_lock_all();
+	for (i = id; i < id + n_groups; i++)
+		set_bit(i, mc_groups);
+	*first_id = id;
+	return 0;
+}
 
-	/* special-case our own group */
-	if (grp == &notify_grp)
-		id = GENL_ID_CTRL;
-	else
-		id = find_first_zero_bit(mc_groups,
-					 mc_groups_longs * BITS_PER_LONG);
+static struct genl_family genl_ctrl;
 
+static int genl_validate_assign_mc_groups(struct genl_family *family)
+{
+	int first_id;
+	int n_groups = family->n_mcgrps;
+	int err = 0, i;
+	bool groups_allocated = false;
 
-	if (id >= mc_groups_longs * BITS_PER_LONG) {
-		size_t nlen = (mc_groups_longs + 1) * sizeof(unsigned long);
+	if (!n_groups)
+		return 0;
 
-		if (mc_groups == &mc_group_start) {
-			new_groups = kzalloc(nlen, GFP_KERNEL);
-			if (!new_groups) {
-				err = -ENOMEM;
-				goto out;
-			}
-			mc_groups = new_groups;
-			*mc_groups = mc_group_start;
-		} else {
-			new_groups = krealloc(mc_groups, nlen, GFP_KERNEL);
-			if (!new_groups) {
-				err = -ENOMEM;
-				goto out;
-			}
-			mc_groups = new_groups;
-			mc_groups[mc_groups_longs] = 0;
-		}
-		mc_groups_longs++;
+	for (i = 0; i < n_groups; i++) {
+		const struct genl_multicast_group *grp = &family->mcgrps[i];
+
+		if (WARN_ON(grp->name[0] == '\0'))
+			return -EINVAL;
+		if (WARN_ON(memchr(grp->name, '\0', GENL_NAMSIZ) == NULL))
+			return -EINVAL;
+	}
+
+	/* special-case our own group and hacks */
+	if (family == &genl_ctrl) {
+		first_id = GENL_ID_CTRL;
+		BUG_ON(n_groups != 1);
+	} else if (strcmp(family->name, "NET_DM") == 0) {
+		first_id = 1;
+		BUG_ON(n_groups != 1);
+	} else if (family->id == GENL_ID_VFS_DQUOT) {
+		first_id = GENL_ID_VFS_DQUOT;
+		BUG_ON(n_groups != 1);
+	} else if (family->id == GENL_ID_PMCRAID) {
+		first_id = GENL_ID_PMCRAID;
+		BUG_ON(n_groups != 1);
+	} else {
+		groups_allocated = true;
+		err = genl_allocate_reserve_groups(n_groups, &first_id);
+		if (err)
+			return err;
 	}
 
+	family->mcgrp_offset = first_id;
+
+	/* if still initializing, can't and don't need to to realloc bitmaps */
+	if (!init_net.genl_sock)
+		return 0;
+
 	if (family->netnsok) {
 		struct net *net;
 
@@ -206,9 +274,7 @@ int genl_register_mc_group(struct genl_family *family,
 				 * number of _possible_ groups has been
 				 * increased on some sockets which is ok.
 				 */
-				rcu_read_unlock();
-				netlink_table_ungrab();
-				goto out;
+				break;
 			}
 		}
 		rcu_read_unlock();
@@ -216,152 +282,67 @@ int genl_register_mc_group(struct genl_family *family,
 	} else {
 		err = netlink_change_ngroups(init_net.genl_sock,
 					     mc_groups_longs * BITS_PER_LONG);
-		if (err)
-			goto out;
 	}
 
-	grp->id = id;
-	set_bit(id, mc_groups);
-	list_add_tail(&grp->list, &family->mcast_groups);
-	grp->family = family;
+	if (groups_allocated && err) {
+		for (i = 0; i < family->n_mcgrps; i++)
+			clear_bit(family->mcgrp_offset + i, mc_groups);
+	}
 
-	genl_ctrl_event(CTRL_CMD_NEWMCAST_GRP, grp);
- out:
-	genl_unlock_all();
 	return err;
 }
-EXPORT_SYMBOL(genl_register_mc_group);
 
-static void __genl_unregister_mc_group(struct genl_family *family,
-				       struct genl_multicast_group *grp)
+static void genl_unregister_mc_groups(struct genl_family *family)
 {
 	struct net *net;
-	BUG_ON(grp->family != family);
+	int i;
 
 	netlink_table_grab();
 	rcu_read_lock();
-	for_each_net_rcu(net)
-		__netlink_clear_multicast_users(net->genl_sock, grp->id);
+	for_each_net_rcu(net) {
+		for (i = 0; i < family->n_mcgrps; i++)
+			__netlink_clear_multicast_users(
+				net->genl_sock, family->mcgrp_offset + i);
+	}
 	rcu_read_unlock();
 	netlink_table_ungrab();
 
-	clear_bit(grp->id, mc_groups);
-	list_del(&grp->list);
-	genl_ctrl_event(CTRL_CMD_DELMCAST_GRP, grp);
-	grp->id = 0;
-	grp->family = NULL;
-}
+	for (i = 0; i < family->n_mcgrps; i++) {
+		int grp_id = family->mcgrp_offset + i;
 
-/**
- * genl_unregister_mc_group - unregister a multicast group
- *
- * Unregisters the specified multicast group and notifies userspace
- * about it. All current listeners on the group are removed.
- *
- * Note: It is not necessary to unregister all multicast groups before
- *       unregistering the family, unregistering the family will cause
- *       all assigned multicast groups to be unregistered automatically.
- *
- * @family: Generic netlink family the group belongs to.
- * @grp: The group to unregister, must have been registered successfully
- *	 previously.
- */
-void genl_unregister_mc_group(struct genl_family *family,
-			      struct genl_multicast_group *grp)
-{
-	genl_lock_all();
-	__genl_unregister_mc_group(family, grp);
-	genl_unlock_all();
+		if (grp_id != 1)
+			clear_bit(grp_id, mc_groups);
+		genl_ctrl_event(CTRL_CMD_DELMCAST_GRP, family,
+				&family->mcgrps[i], grp_id);
+	}
 }
-EXPORT_SYMBOL(genl_unregister_mc_group);
 
-static void genl_unregister_mc_groups(struct genl_family *family)
+static int genl_validate_ops(struct genl_family *family)
 {
-	struct genl_multicast_group *grp, *tmp;
+	const struct genl_ops *ops = family->ops;
+	unsigned int n_ops = family->n_ops;
+	int i, j;
 
-	list_for_each_entry_safe(grp, tmp, &family->mcast_groups, list)
-		__genl_unregister_mc_group(family, grp);
-}
-
-/**
- * genl_register_ops - register generic netlink operations
- * @family: generic netlink family
- * @ops: operations to be registered
- *
- * Registers the specified operations and assigns them to the specified
- * family. Either a doit or dumpit callback must be specified or the
- * operation will fail. Only one operation structure per command
- * identifier may be registered.
- *
- * See include/net/genetlink.h for more documenation on the operations
- * structure.
- *
- * Returns 0 on success or a negative error code.
- */
-int genl_register_ops(struct genl_family *family, struct genl_ops *ops)
-{
-	int err = -EINVAL;
+	if (WARN_ON(n_ops && !ops))
+		return -EINVAL;
 
-	if (ops->dumpit == NULL && ops->doit == NULL)
-		goto errout;
+	if (!n_ops)
+		return 0;
 
-	if (genl_get_cmd(ops->cmd, family)) {
-		err = -EEXIST;
-		goto errout;
+	for (i = 0; i < n_ops; i++) {
+		if (ops[i].dumpit == NULL && ops[i].doit == NULL)
+			return -EINVAL;
+		for (j = i + 1; j < n_ops; j++)
+			if (ops[i].cmd == ops[j].cmd)
+				return -EINVAL;
 	}
 
-	if (ops->dumpit)
-		ops->flags |= GENL_CMD_CAP_DUMP;
-	if (ops->doit)
-		ops->flags |= GENL_CMD_CAP_DO;
-	if (ops->policy)
-		ops->flags |= GENL_CMD_CAP_HASPOL;
+	/* family is not registered yet, so no locking needed */
+	family->ops = ops;
+	family->n_ops = n_ops;
 
-	genl_lock_all();
-	list_add_tail(&ops->ops_list, &family->ops_list);
-	genl_unlock_all();
-
-	genl_ctrl_event(CTRL_CMD_NEWOPS, ops);
-	err = 0;
-errout:
-	return err;
-}
-EXPORT_SYMBOL(genl_register_ops);
-
-/**
- * genl_unregister_ops - unregister generic netlink operations
- * @family: generic netlink family
- * @ops: operations to be unregistered
- *
- * Unregisters the specified operations and unassigns them from the
- * specified family. The operation blocks until the current message
- * processing has finished and doesn't start again until the
- * unregister process has finished.
- *
- * Note: It is not necessary to unregister all operations before
- *       unregistering the family, unregistering the family will cause
- *       all assigned operations to be unregistered automatically.
- *
- * Returns 0 on success or a negative error code.
- */
-int genl_unregister_ops(struct genl_family *family, struct genl_ops *ops)
-{
-	struct genl_ops *rc;
-
-	genl_lock_all();
-	list_for_each_entry(rc, &family->ops_list, ops_list) {
-		if (rc == ops) {
-			list_del(&ops->ops_list);
-			genl_unlock_all();
-			genl_ctrl_event(CTRL_CMD_DELOPS, ops);
-			return 0;
-		}
-	}
-	genl_unlock_all();
-
-	return -ENOENT;
+	return 0;
 }
-EXPORT_SYMBOL(genl_unregister_ops);
 
 /**
  * __genl_register_family - register a generic netlink family
@@ -372,11 +353,14 @@ EXPORT_SYMBOL(genl_unregister_ops);
  * The family id may equal GENL_ID_GENERATE causing an unique id to
  * be automatically generated and assigned.
  *
+ * The family's ops array must already be assigned, you can use the
+ * genl_register_family_with_ops() helper function.
+ *
  * Return 0 on success or a negative error code.
  */
 int __genl_register_family(struct genl_family *family)
 {
-	int err = -EINVAL;
+	int err = -EINVAL, i;
 
 	if (family->id && family->id < GENL_MIN_ID)
 		goto errout;
@@ -384,8 +368,9 @@ int __genl_register_family(struct genl_family *family)
 	if (family->id > GENL_MAX_ID)
 		goto errout;
 
-	INIT_LIST_HEAD(&family->ops_list);
-	INIT_LIST_HEAD(&family->mcast_groups);
+	err = genl_validate_ops(family);
+	if (err)
+		return err;
 
 	genl_lock_all();
 
@@ -418,10 +403,18 @@ int __genl_register_family(struct genl_family *family)
 	} else
 		family->attrbuf = NULL;
 
+	err = genl_validate_assign_mc_groups(family);
+	if (err)
+		goto errout_locked;
+
 	list_add_tail(&family->family_list, genl_family_chain(family->id));
 	genl_unlock_all();
 
-	genl_ctrl_event(CTRL_CMD_NEWFAMILY, family);
+	/* send all events */
+	genl_ctrl_event(CTRL_CMD_NEWFAMILY, family, NULL, 0);
+	for (i = 0; i < family->n_mcgrps; i++)
+		genl_ctrl_event(CTRL_CMD_NEWMCAST_GRP, family,
+				&family->mcgrps[i], family->mcgrp_offset + i);
 
 	return 0;
 
@@ -433,52 +426,6 @@ errout:
 EXPORT_SYMBOL(__genl_register_family);
 
 /**
- * __genl_register_family_with_ops - register a generic netlink family
- * @family: generic netlink family
- * @ops: operations to be registered
- * @n_ops: number of elements to register
- *
- * Registers the specified family and operations from the specified table.
- * Only one family may be registered with the same family name or identifier.
- *
- * The family id may equal GENL_ID_GENERATE causing an unique id to
- * be automatically generated and assigned.
- *
- * Either a doit or dumpit callback must be specified for every registered
- * operation or the function will fail. Only one operation structure per
- * command identifier may be registered.
- *
- * See include/net/genetlink.h for more documenation on the operations
- * structure.
- *
- * This is equivalent to calling genl_register_family() followed by
- * genl_register_ops() for every operation entry in the table taking
- * care to unregister the family on error path.
- *
- * Return 0 on success or a negative error code.
- */
-int __genl_register_family_with_ops(struct genl_family *family,
-	struct genl_ops *ops, size_t n_ops)
-{
-	int err, i;
-
-	err = __genl_register_family(family);
-	if (err)
-		return err;
-
-	for (i = 0; i < n_ops; ++i, ++ops) {
-		err = genl_register_ops(family, ops);
-		if (err)
-			goto err_out;
-	}
-	return 0;
-err_out:
-	genl_unregister_family(family);
-	return err;
-}
-EXPORT_SYMBOL(__genl_register_family_with_ops);
-
-/**
  * genl_unregister_family - unregister generic netlink family
  * @family: generic netlink family
  *
@@ -499,11 +446,11 @@ int genl_unregister_family(struct genl_family *family)
 			continue;
 
 		list_del(&rc->family_list);
-		INIT_LIST_HEAD(&family->ops_list);
+		family->n_ops = 0;
 		genl_unlock_all();
 
 		kfree(family->attrbuf);
-		genl_ctrl_event(CTRL_CMD_DELFAMILY, family);
+		genl_ctrl_event(CTRL_CMD_DELFAMILY, family, NULL, 0);
 		return 0;
 	}
 
@@ -546,7 +493,8 @@ EXPORT_SYMBOL(genlmsg_put);
 
 static int genl_lock_dumpit(struct sk_buff *skb, struct netlink_callback *cb)
 {
-	struct genl_ops *ops = cb->data;
+	/* our ops are always const - netlink API doesn't propagate that */
+	const struct genl_ops *ops = cb->data;
 	int rc;
 
 	genl_lock();
@@ -557,7 +505,8 @@ static int genl_lock_dumpit(struct sk_buff *skb, struct netlink_callback *cb)
 
 static int genl_lock_done(struct netlink_callback *cb)
 {
-	struct genl_ops *ops = cb->data;
+	/* our ops are always const - netlink API doesn't propagate that */
+	const struct genl_ops *ops = cb->data;
 	int rc = 0;
 
 	if (ops->done) {
@@ -572,7 +521,7 @@ static int genl_family_rcv_msg(struct genl_family *family,
 			       struct sk_buff *skb,
 			       struct nlmsghdr *nlh)
 {
-	struct genl_ops *ops;
+	const struct genl_ops *ops;
 	struct net *net = sock_net(skb->sk);
 	struct genl_info info;
 	struct genlmsghdr *hdr = nlmsg_data(nlh);
@@ -604,7 +553,8 @@ static int genl_family_rcv_msg(struct genl_family *family,
 		if (!family->parallel_ops) {
 			struct netlink_dump_control c = {
 				.module = family->module,
-				.data = ops,
+				/* we have const, but the netlink API doesn't */
+				.data = (void *)ops,
 				.dump = genl_lock_dumpit,
 				.done = genl_lock_done,
 			};
@@ -726,24 +676,32 @@ static int ctrl_fill_info(struct genl_family *family, u32 portid, u32 seq,
 	    nla_put_u32(skb, CTRL_ATTR_MAXATTR, family->maxattr))
 		goto nla_put_failure;
 
-	if (!list_empty(&family->ops_list)) {
+	if (family->n_ops) {
 		struct nlattr *nla_ops;
-		struct genl_ops *ops;
-		int idx = 1;
+		int i;
 
 		nla_ops = nla_nest_start(skb, CTRL_ATTR_OPS);
 		if (nla_ops == NULL)
 			goto nla_put_failure;
 
-		list_for_each_entry(ops, &family->ops_list, ops_list) {
+		for (i = 0; i < family->n_ops; i++) {
 			struct nlattr *nest;
+			const struct genl_ops *ops = &family->ops[i];
+			u32 op_flags = ops->flags;
 
-			nest = nla_nest_start(skb, idx++);
+			if (ops->dumpit)
+				op_flags |= GENL_CMD_CAP_DUMP;
+			if (ops->doit)
+				op_flags |= GENL_CMD_CAP_DO;
+			if (ops->policy)
+				op_flags |= GENL_CMD_CAP_HASPOL;
+
+			nest = nla_nest_start(skb, i + 1);
 			if (nest == NULL)
 				goto nla_put_failure;
 
 			if (nla_put_u32(skb, CTRL_ATTR_OP_ID, ops->cmd) ||
-			    nla_put_u32(skb, CTRL_ATTR_OP_FLAGS, ops->flags))
+			    nla_put_u32(skb, CTRL_ATTR_OP_FLAGS, op_flags))
 				goto nla_put_failure;
 
 			nla_nest_end(skb, nest);
@@ -752,23 +710,26 @@ static int ctrl_fill_info(struct genl_family *family, u32 portid, u32 seq,
 		nla_nest_end(skb, nla_ops);
 	}
 
-	if (!list_empty(&family->mcast_groups)) {
-		struct genl_multicast_group *grp;
+	if (family->n_mcgrps) {
 		struct nlattr *nla_grps;
-		int idx = 1;
+		int i;
 
 		nla_grps = nla_nest_start(skb, CTRL_ATTR_MCAST_GROUPS);
 		if (nla_grps == NULL)
 			goto nla_put_failure;
 
-		list_for_each_entry(grp, &family->mcast_groups, list) {
+		for (i = 0; i < family->n_mcgrps; i++) {
 			struct nlattr *nest;
+			const struct genl_multicast_group *grp;
+
+			grp = &family->mcgrps[i];
 
-			nest = nla_nest_start(skb, idx++);
+			nest = nla_nest_start(skb, i + 1);
 			if (nest == NULL)
 				goto nla_put_failure;
 
-			if (nla_put_u32(skb, CTRL_ATTR_MCAST_GRP_ID, grp->id) ||
+			if (nla_put_u32(skb, CTRL_ATTR_MCAST_GRP_ID,
+					family->mcgrp_offset + i) ||
 			    nla_put_string(skb, CTRL_ATTR_MCAST_GRP_NAME,
 					   grp->name))
 				goto nla_put_failure;
@@ -785,9 +746,10 @@ nla_put_failure:
 	return -EMSGSIZE;
 }
 
-static int ctrl_fill_mcgrp_info(struct genl_multicast_group *grp, u32 portid,
-				u32 seq, u32 flags, struct sk_buff *skb,
-				u8 cmd)
+static int ctrl_fill_mcgrp_info(struct genl_family *family,
+				const struct genl_multicast_group *grp,
+				int grp_id, u32 portid, u32 seq, u32 flags,
+				struct sk_buff *skb, u8 cmd)
 {
 	void *hdr;
 	struct nlattr *nla_grps;
@@ -797,8 +759,8 @@ static int ctrl_fill_mcgrp_info(struct genl_multicast_group *grp, u32 portid,
 	if (hdr == NULL)
 		return -1;
 
-	if (nla_put_string(skb, CTRL_ATTR_FAMILY_NAME, grp->family->name) ||
-	    nla_put_u16(skb, CTRL_ATTR_FAMILY_ID, grp->family->id))
+	if (nla_put_string(skb, CTRL_ATTR_FAMILY_NAME, family->name) ||
+	    nla_put_u16(skb, CTRL_ATTR_FAMILY_ID, family->id))
 		goto nla_put_failure;
 
 	nla_grps = nla_nest_start(skb, CTRL_ATTR_MCAST_GROUPS);
@@ -809,7 +771,7 @@ static int ctrl_fill_mcgrp_info(struct genl_multicast_group *grp, u32 portid,
 	if (nest == NULL)
 		goto nla_put_failure;
 
-	if (nla_put_u32(skb, CTRL_ATTR_MCAST_GRP_ID, grp->id) ||
+	if (nla_put_u32(skb, CTRL_ATTR_MCAST_GRP_ID, grp_id) ||
 	    nla_put_string(skb, CTRL_ATTR_MCAST_GRP_NAME,
 			   grp->name))
 		goto nla_put_failure;
@@ -875,8 +837,10 @@ static struct sk_buff *ctrl_build_family_msg(struct genl_family *family,
 	return skb;
 }
 
-static struct sk_buff *ctrl_build_mcgrp_msg(struct genl_multicast_group *grp,
-					    u32 portid, int seq, u8 cmd)
+static struct sk_buff *
+ctrl_build_mcgrp_msg(struct genl_family *family,
+		     const struct genl_multicast_group *grp,
+		     int grp_id, u32 portid, int seq, u8 cmd)
 {
 	struct sk_buff *skb;
 	int err;
@@ -885,7 +849,8 @@ static struct sk_buff *ctrl_build_mcgrp_msg(struct genl_multicast_group *grp,
 	if (skb == NULL)
 		return ERR_PTR(-ENOBUFS);
 
-	err = ctrl_fill_mcgrp_info(grp, portid, seq, 0, skb, cmd);
+	err = ctrl_fill_mcgrp_info(family, grp, grp_id, portid,
+				   seq, 0, skb, cmd);
 	if (err < 0) {
 		nlmsg_free(skb);
 		return ERR_PTR(err);
@@ -947,11 +912,11 @@ static int ctrl_getfamily(struct sk_buff *skb, struct genl_info *info)
 	return genlmsg_reply(msg, info);
 }
 
-static int genl_ctrl_event(int event, void *data)
+static int genl_ctrl_event(int event, struct genl_family *family,
+			   const struct genl_multicast_group *grp,
+			   int grp_id)
 {
 	struct sk_buff *msg;
-	struct genl_family *family;
-	struct genl_multicast_group *grp;
 
 	/* genl is still initialising */
 	if (!init_net.genl_sock)
@@ -960,14 +925,13 @@ static int genl_ctrl_event(int event, void *data)
 	switch (event) {
 	case CTRL_CMD_NEWFAMILY:
 	case CTRL_CMD_DELFAMILY:
-		family = data;
+		WARN_ON(grp);
 		msg = ctrl_build_family_msg(family, 0, 0, event);
 		break;
 	case CTRL_CMD_NEWMCAST_GRP:
 	case CTRL_CMD_DELMCAST_GRP:
-		grp = data;
-		family = grp->family;
-		msg = ctrl_build_mcgrp_msg(data, 0, 0, event);
+		BUG_ON(!grp);
+		msg = ctrl_build_mcgrp_msg(family, grp, grp_id, 0, 0, event);
 		break;
 	default:
 		return -EINVAL;
@@ -977,26 +941,29 @@ static int genl_ctrl_event(int event, void *data)
 		return PTR_ERR(msg);
 
 	if (!family->netnsok) {
-		genlmsg_multicast_netns(&init_net, msg, 0,
-					GENL_ID_CTRL, GFP_KERNEL);
+		genlmsg_multicast_netns(&genl_ctrl, &init_net, msg, 0,
+					0, GFP_KERNEL);
 	} else {
 		rcu_read_lock();
-		genlmsg_multicast_allns(msg, 0, GENL_ID_CTRL, GFP_ATOMIC);
+		genlmsg_multicast_allns(&genl_ctrl, msg, 0,
+					0, GFP_ATOMIC);
 		rcu_read_unlock();
 	}
 
 	return 0;
 }
 
-static struct genl_ops genl_ctrl_ops = {
-	.cmd		= CTRL_CMD_GETFAMILY,
-	.doit		= ctrl_getfamily,
-	.dumpit		= ctrl_dumpfamily,
-	.policy		= ctrl_policy,
+static struct genl_ops genl_ctrl_ops[] = {
+	{
+		.cmd		= CTRL_CMD_GETFAMILY,
+		.doit		= ctrl_getfamily,
+		.dumpit		= ctrl_dumpfamily,
+		.policy		= ctrl_policy,
+	},
 };
 
-static struct genl_multicast_group notify_grp = {
-	.name		= "notify",
+static struct genl_multicast_group genl_ctrl_groups[] = {
+	{ .name = "notify", },
 };
 
 static int __net_init genl_pernet_init(struct net *net)
@@ -1036,7 +1003,8 @@ static int __init genl_init(void)
 	for (i = 0; i < GENL_FAM_TAB_SIZE; i++)
 		INIT_LIST_HEAD(&family_ht[i]);
 
-	err = genl_register_family_with_ops(&genl_ctrl, &genl_ctrl_ops, 1);
+	err = genl_register_family_with_ops_groups(&genl_ctrl, genl_ctrl_ops,
+						   genl_ctrl_groups);
 	if (err < 0)
 		goto problem;
 
@@ -1044,10 +1012,6 @@ static int __init genl_init(void)
 	if (err)
 		goto problem;
 
-	err = genl_register_mc_group(&genl_ctrl, &notify_grp);
-	if (err < 0)
-		goto problem;
-
 	return 0;
 
 problem:
@@ -1085,14 +1049,18 @@ static int genlmsg_mcast(struct sk_buff *skb, u32 portid, unsigned long group,
 	return err;
 }
 
-int genlmsg_multicast_allns(struct sk_buff *skb, u32 portid, unsigned int group,
-			    gfp_t flags)
+int genlmsg_multicast_allns(struct genl_family *family, struct sk_buff *skb,
+			    u32 portid, unsigned int group, gfp_t flags)
 {
+	if (WARN_ON_ONCE(group >= family->n_mcgrps))
+		return -EINVAL;
+	group = family->mcgrp_offset + group;
 	return genlmsg_mcast(skb, portid, group, flags);
 }
 EXPORT_SYMBOL(genlmsg_multicast_allns);
 
-void genl_notify(struct sk_buff *skb, struct net *net, u32 portid, u32 group,
+void genl_notify(struct genl_family *family,
+		 struct sk_buff *skb, struct net *net, u32 portid, u32 group,
 		 struct nlmsghdr *nlh, gfp_t flags)
 {
 	struct sock *sk = net->genl_sock;
@@ -1101,6 +1069,9 @@ void genl_notify(struct sk_buff *skb, struct net *net, u32 portid, u32 group,
 	if (nlh)
 		report = nlmsg_report(nlh);
 
+	if (WARN_ON_ONCE(group >= family->n_mcgrps))
+		return;
+	group = family->mcgrp_offset + group;
 	nlmsg_notify(sk, skb, portid, group, report, flags);
 }
 EXPORT_SYMBOL(genl_notify);